Showing papers in "Food and Bioprocess Technology in 2015"

An Overview of 3D Printing Technologies for Food Fabrication

Abstract: Different from robotics-based food manufacturing, three-dimensional (3D) food printing integrates 3D printing and digital gastronomy to revolutionize food manufacturing with customized shape, color, flavor, texture, and even nutrition. Hence, food products can be designed and fabricated to meet individual needs through controlling the amount of printing material and nutrition content. The objectives of this study are to collate, analyze, categorize, and summarize published articles and papers pertaining to 3D food printing and its impact on food processing, as well as to provide a critical insight into the direction of its future development. From the available references, both universal platforms and self-developed platforms are utilized for food printing. These platforms could be reconstructed in terms of process reformulation, material processing, and user interface in the near future. Three types of printing materials (i.e., natively printable materials, non-printable traditional food materials, and alternative ingredients) and two types of recipes (i.e., element-based recipe and traditional recipe) have been used for customized food fabrication. The available 3D food printing technologies and food processing technologies potentially applicable to food printing are presented. Essentially, 3D food printing provides an engineering solution for customized food design and personalized nutrition control, a prototyping tool to facilitate new food product development, and a potential machine to reconfigure a customized food supply chain.

High Voltage Electrical Discharges, Pulsed Electric Field, and Ultrasound Assisted Extraction of Protein and Phenolic Compounds from Olive Kernel

Abstract: The study was aimed at improvement of recovery of intracellular valuable compounds from olive kernels (Olea europaea). High voltage electrical discharges (HVED), pulsed electric field (PEF), and ultrasound (US) were applied as pretreatments before extraction. The influence of HVED energy input (0–109 kJ/kg), pH (2.5–12), and ethanol (0–50 %) on the efficiency of the extraction was studied. The extracts obtained immediately after pretreatments were analyzed for total phenolic compounds, antioxidant activity, proteins, and pigments. HVED treatment was demonstrated to be more effective than ultrasound and pulsed electric field in terms of energy input and effective treatment time to extract phenolic compounds and proteins. Moreover, the application of HVED increased significantly the aqueous and hydro-ethanolic extractions of total phenolic content (TPC), and proteins of the recovered extracts when energy input was augmented. pH and ethanol percentage had also a significant influence in TPC, protein, and antioxidant recovery. The interesting observation is that pH 2.5 resulted in the optimum conditions to recover TPC and antioxidant capacity. However, the higher protein content was found when pH 12 was used. Multiple response optimization showed that TPC, content of proteins, and antioxidant capacity (Trolox equivalent antioxidant capacity (TEAC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) values) of the sample were further maximized after HVED pretreatment at energy input 66 kJ/kg at pH 2.5 followed by extraction in 49 % ethanol. TPC, content of proteins, TEAC, and DPPH values under such conditions of extraction were 626.6 mg GAE/L, 0.225 mg/mL, 9.80 mM TE, and 7.61 mM TE, respectively.

Kinetics of Food Quality Changes During Thermal Processing: a Review

Abstract: Thermal treatments are extensively used in the food industry for control of pathogenic and spoilage microorganisms and spoilage enzymes. Food quality degradation during those treatments can be a major concern for consumer acceptance. Kinetic studies and mathematical models on quality changes of foods are essential in proper design of thermal treatments to ensure consumer satisfaction. This study provides a comprehensive review of recent progresses on quality kinetics for thermal treatments to inactivate microorganisms and enzymes in foods of both plant and animal origins. This paper mainly covers the theoretical basis for studying quality kinetics, common and special kinetic models to describe major quality attributes, such as appearance, texture, and nutrients, and potential applications of quality kinetic models to developing thermal treatment protocols. Finally, this review describes the challenges in quality kinetic studies and proposes recommendations for future research to maintain food quality and extend shelf life.

Effect of Alternative Physical Treatments (Ultrasounds, Pulsed Electric Fields, and High-Voltage Electrical Discharges) on Selective Recovery of Bio-compounds from Fermented Grape Pomace

Abstract: The aim of this study is to compare alternative treatments on solvent-free extraction of high added value components from fermented grape pomace. Ultrasounds (US), pulsed electric fields (PEF) and high voltage electric discharges (HVED), which are physical treatments able to induce cell damages, were applied on aqueous suspensions of grape pomace. The efficiency of these technologies for phenolic compounds extraction, and particularly for anthocyanins recovery, was evaluated throughout the treatments at equivalent cell disintegration indexes (Z). HVED proved to be the most interesting technique to achieve higher phenolic compounds recovery with lower energy requirement than PEF and US at the same values of Z. However, HVED was less selective than PEF and US regarding the amount of anthocyanins recovered. At equivalent cell disintegration of Z = 0.8, PEF remarkably increased the extraction yield of total anthocyanins up to 22 and 55 % in comparison with US and HVED-assisted extractions. At this Z value, the ratio of total anthocyanins to TPC extracted reaches the respective values of 41.7, 34.9 and 14.1 % for PEF, US and HVED, thus demonstrating interesting differences of selectivity of the treatments.

A Review of Novel and Innovative Food Freezing Technologies

Abstract: Freezing is a very well-established food preservation process that produces high quality nutritious foods with a long storage life. However, freezing is not suitable for all foods, and freezing can cause physical and chemical changes in some foods that are perceived as reducing the quality of either the thawed material or the final product. This paper reviews the many innovative freezing processes that are currently being researched and developed throughout the world to improve freezing conditions and product quality. Some innovative freezing processes (impingement and hydrofluidisation) are essentially improvements of existing methods (air blast and immersion, respectively) to produce far higher surface heat transfer rates than previous systems and thus improve product quality through rapid freezing. In these cases, the advantages may depend on the size of the product, since the poor thermal conductivity of many foods limits the rate of cooling in large objects rather than the heat transfer between the heat transfer medium and the product. Other processes (pressure shift, magnetic resonance, electrostatic, microwave, radiofrequency, and ultrasound) are adjuncts to existing freezing systems that aim to improve product quality through controlling the way that ice is formed in the food during freezing. Another alternative is to change the properties of the food itself to control how ice is formed during freezing (such as in dehydrofreezing and the use of antifreeze and ice-nucleation proteins).

The Effect of Chitosan Coating on the Quality and Nutraceutical Traits of Sweet Cherry During Postharvest Life

Abstract: The effectiveness of a chitosan-coating treatment on the physical and chemical, nutraceutical, and sensorial traits of three sweet cherry cultivar (Prunus avium L., namely cvs. “Ferrovia,” “Lapins,” “Della Recca”) harvested at the commercial ripening stage was evaluated. Fruits were treated with a 0.5 % chitosan coating, stored at 2 °C for 14 days, and sampled weekly followed by storage at 24 °C for 3 days to assess the shelf life of the fruit. Physical-chemical (weight loss, soluble solid content, and titratable acidity), nutraceutical (total polyphenol, anthocyanin, flavonoid, ascorbic acid content, antioxidant capacity), and sensory (fruit juiciness, sweetness, sourness, texture, and taste) evaluations were performed. A chitosan coating significantly reduced the water loss and delayed the changes in color, titratable acidity, ascorbic acid content, and respiration rate in a cultivar-dependent manner. Additionally, changes in the total polyphenol, anthocyanin, and flavonoid content and in the antioxidant capacity of the chitosan-coated sweet cherry fruits were delayed. This treatment extended the postharvest life, improved the storability, and enhanced the nutraceutical value of sweet cherry.

Assessment of Visible Near-Infrared Hyperspectral Imaging as a Tool for Detection of Horsemeat Adulteration in Minced Beef

Abstract: For the first time, a visible near-infrared (Vis-NIR) hyperspectral imaging system (400–1000 nm) was investigated for rapid and non-destructive detection of adulteration in minced beef meat. Minced beef meat samples were adulterated with horsemeat at levels ranging from 2 to 50 % (w/w), at approximately 2 % increments. Calibration model was developed and optimized using partial least-squares regression (PLSR) with internal full cross-validation and then validated by external validation using an independent validation set. Several spectral pre-treatment techniques including derivatives, standard normal variate (SNV), and multiplicative scatter correction (MSC) were applied to examine the influence of spectral variations for predicting adulteration in minced beef. The established PLSR models based on raw spectra had coefficients of determination (R2) of 0.99, 0.99, and 0.98, and standard errors of 1.14, 1.56, and 2.23 % for calibration, cross-validation, and prediction, respectively. Four important wavelengths (515, 595, 650, and 880 nm) were selected using regression coefficients resulting from the best PLSR model. By using these important wavelengths, an image processing algorithm was developed to predict the adulteration level in each pixel in whole surface of the samples. The results demonstrate that hyperspectral imaging coupled with multivariate analysis can be successfully applied as a rapid screening technique for adulterate detection in minced meat.

Double Emulsions: Emerging Delivery System for Plant Bioactives

Abstract: Bioactives have shown excellent protective effect against chronic diseases such as cancer, cardiovascular diseases and metabolic disorders. However, many of the bioactives like anthocyanins, carotenoids, flavonoids, vitamins and essential fatty acids are sensitive to surrounding environment stresses like pH, ionic strength, light, temperature, oxygen and gastro-intestinal (GI) conditions during transit. Hence, the functionality diminishes upon exposure to such unfriendly environment and leads to reduction in bioavailability. Double emulsions are designed to provide protection to bioactives in the innermost compartment through encapsulation and prevent loss of functionality in food matrix as well as during the GI transit. This article reviews the work done on double emulsion for food applications, covering various aspects of double emulsion like its matrix, constituents (aqueous phase, oil phase, emulsifiers, and other additives) and properties (viscosity, particle size, electrical conductivity and zeta potential). In addition to the stability of double emulsion, various means to express and modern techniques to measure it, the review also elucidates the role of newer emulsifiers and additives in improving the stability of double emulsion. The developments in target delivery of bioactives through double emulsion are highlighted. In vitro and in vivo studies proved target delivery of bioactives through double emulsion; however, confirmation through human trial is still pending.

Techniques for Extraction of Green Tea Polyphenols: A Review

Abstract: Tea is the second most consumed beverage all over the world after water. In recent times, tea has stretched the eyebrows of researchers and catching all the attention towards its health benefits. Tea has been proven beneficial by preventing the risk of some diseases like cancer and cardiovascular problems. Green tea is least processed and gives maximum benefits. The main components of the green tea are polyphenols which include the catechins, epicatechins, epigallocatechins, epicatechingallate, epigallocatechingallate, gallic acid, flavanoids, flavanols, and flavonols. Other than polyphenols, caffeine and theophylline are also present. Among which compounds of catechins family has been widely reported to have most beneficial effects on the health. Currently, the extraction of catechins is catching much higher attention and many techniques have been discovered and modified to extract these compounds. But very limited reviews have been reported discussing the impact of various techniques used for extraction of green tea polyphenols. This review focuses on various techniques employed for the extraction of polyphenols from green tea and other sources (pine bark, grape seed, and pomegranate) with their advantages and limitations. The current trends and future prospects are also highlighted.

Effect of ultrasound immersion freezing on the quality attributes and water distributions of wrapped red radish

Abstract: The microstructures, quality attributes (drip loss, firmness, sensory evaluation, and calcium content), and water distributions of ultrasound immersion frozen red radish (wrapped or unwrapped) were investigated. The results showed that ultrasonic treatment can significantly (p < 0.05) decrease the freezing time and better preserve the quality of frozen radish samples. In addition, ultrasound immersion frozen radish samples had smaller pore size and less destructive effect on microstructures from the scan electron microscopy (SEM) analysis. Wrapped radish had significantly (p < 0.05) lower calcium content, indicating that wrapped treatment was able to effectively prevent the solute uptake from the coolant to the radish samples. The water distributions of unwrapped samples were more uniform from the pseudocolor images of magnetic resonance imaging (MRI). Low-field nuclear magnetic resonance (LF-NMR) relaxation measurements showed that the vacuole water decreased, while the relative cytoplasm and intercellular space water increased under ultrasonic and unwrapped treatment.

Comparison of Partial Least Squares Regression (PLSR) and Principal Components Regression (PCR) Methods for Protein and Hardness Predictions using the Near-Infrared (NIR) Hyperspectral Images of Bulk Samples of Canadian Wheat

Abstract: The objective of this study was to compare the predictions of the protein contents and hardness values by partial least squares regression (PLSR) and principal components regression (PCR) models for bulk samples of Canadian wheat, which were obtained from different locations and crop years. Wheat samples of Canada Western Red Spring (CWRS), Canada Western Hard White Spring (CWHWS), Canada Western Soft White Spring (CWSWS), and Canada Prairie Spring Red (CPSR) classes were obtained from nearby agricultural farms in the main wheat growing locations in the Provinces of Alberta, Saskatchewan, and Manitoba from 2007, 2008, and 2009 crop years. Wheat samples were conditioned to moisture levels of 13, 16, and 19 % (wet basis) and pooled together for developing the regression models. A database of the near-infrared (NIR) hyperspectral image cubes of bulk samples of wheat classes was created in the wavelength region of 960–1,700 nm with 10 nm intervals. Reference protein contents and hardness values were determined using the Dumatherm method and single kernel characterization system (SKCS), respectively. A tenfold cross-validation was used for the ten-factor partial least squares regression (PLSR) and principal components regression (PCR) models for prediction purposes. Prediction performances of regression models were assessed by calculating the estimated mean square errors of prediction (MSEP), standard error of cross-validation (SECV), and correlation coefficient (r). Using the full data set in the protein prediction study, the ten-component PLSR model gave 1.76, 1.33, and 0.68 for the estimated MSEP, SECV, and r, respectively, which were better than the results for the ten-component PCR model (2.02, 1.42, and 0.62, respectively). For the hardness prediction, the estimated MSEP, SECV, and r values were 147.7, 12.15, and 0.82, respectively, for the ten-component PLSR model using the full data set. The PLSR models prediction performances outperformed the PCR models for predicting protein contents and hardness of wheat.

Morphology and Stability of Edible Lycopene-Containing Micro- and Nanocapsules Produced Through Electrospraying and Spray Drying

Abstract: In this work, lycopene was encapsulated through electrospraying and spray drying (using a microporous membrane cap) within different edible biopolymeric matrices. Specifically, dextran, a whey protein concentrate (WPC) and chitosan were used as matrix materials. As a strategy to incorporate the hydrophobic bioactive within the hydrophilic matrices, emulsion electrospraying and spray drying from emulsion were carried out. Moreover and for comparison purposes, coaxial electrospraying was also performed. The electrospraying solutions properties were studied, since they do not only affect the success of the electrohydrodynamic process but also influence the morphology of the capsules. Apart from characterizing the morphology and molecular organization of the developed capsules, the encapsulation efficiency and the lycopene stability under moisture and heating conditions were also evaluated. Results showed that even though encapsulation structures were obtained from all the matrices assayed through both processing technologies, spray drying, as a consequence of the high temperatures needed in this process, affected lycopene stability and very poor encapsulation efficiencies were found in this case. It was also seen that WPC presented the greatest encapsulation efficiency (around 75 %), probably ascribed to the interactions between the biopolymer and the lycopene. Furthermore, WPC capsules were able to better protect lycopene against moisture and thermal degradation.

Rapid Quantification Analysis and Visualization of Escherichia coli Loads in Grass Carp Fish Flesh by Hyperspectral Imaging Method

Abstract: Microbial contamination during fish flesh spoilage process can easily induce food-borne outbreaks and consumer health problems. Hyperspectral imaging in the spectral range of 400–1000 nm was developed to measure the Escherichia coli (E. coli) loads in grass carp fish for evaluation and visualization of microbial spoilage. Partial least square regression (PLSR) model was conducted to build prediction models between the spectral data and the reference E. coli loads estimated by classical microbiological plating method. The PLSR model based on full wavelengths showed good performance on predicting E. coli loads with the residual predictive deviation (RPD) of 5.47 and determination coefficient of R2P = 0.880. Six characteristic wavelengths were selected by the weighted regression coefficients from PLSR analysis and used to simplify the models. The simplified PLSR and multiple linear regression (MLR) models also presented good prediction capability. The better simplified MLR model (RPD = 5.22 and R2P = 0.870) was used to transfer each pixel in the image for visualizing the spatial distribution of E. coli loads. The results demonstrated that hyperspectral imaging technique with multivariate analysis has the potential to rapidly and non-invasively quantify and visualize the E. coli loads in grass carp fish flesh during the spoilage process.

Microencapsulation by Complex Coacervation Using Whey Protein Isolates and Gum Acacia: An Approach to Preserve the Functionality and Controlled Release of β-Carotene

Abstract: β-Carotene is a red–orange pigment, a known source of vitamin A and has exceptional antioxidant and free radical scavenging potential. However, uses of β-carotene in food industry are inadequate mostly because of their poor water solubility and low stability. Using the complex coacervation technique, the work is meant to fabricate the microcapsules of β-carotene, to examine the physicochemical properties of microcapsules and finally to evaluate the extent of stability improvement. The configuration of electrostatic complexes between whey protein isolate (WPI) and gum acacia (Acacia arabica, GA) was optimized as a function of pH, ionic strength, WPI/GA ratio, core material load and size of final micromolecules. The optimum process conditions were balanced by the ratio of wall materials WPI/GA 2.0/1.0 % and pH value 4.2. Morphological observations showed that microcapsules presented spherical shape, and smooth and continuous surface. The effective amount of encapsulated core was greater than 70 % for all formulations evaluated. In vitro release data indicated an initial burst release followed by sustained release behavior. The microstructure and viscoelastic properties of WPI and GA complex were studied using dynamic rheometer. The encapsulation method and the wall materials used in this work gave effective protection during storage and eventually resulted sustained release of bioactive while used in food matrix, at suitable conditions.

Effects of Adenosine Triphosphate (ATP) Treatment on Postharvest Physiology, Quality and Storage Behavior of Longan Fruit

Abstract: The effects of adenosine triphosphate (ATP) on postharvest physiology, quality, and storage behavior of harvested longan fruit were investigated. Fruit of “Fuyan” longan were dipped in 0.8 mM ATP solution or distilled water (control) for 20 min. The fruit were dried prior to packaging and then stored at 28 °C and 90 % relative humidity. The results showed that as compared with control fruit, application of ATP could significantly reduce fruit respiration rate; delay an increase of cell membrane permeability in pericarp; maintain higher contents of chlorophyll, carotenoid, anthocyanin, and flavonoid; and subsequently retard the change of apparent color on longans. In addition, lower polyphenol oxidase (PPO) activity and higher total phenolics content were also found in ATP-treated fruit, which contributed to lower browning index in longan pericarp. The application of ATP could effectively inhibit the decreases in contents of total soluble solids (TSS), total soluble sugars, and vitamin C with a limited increase of titratable acidity (TA) content in pulp, which maintain better quality and flavor in longan pulp. Furthermore, ATP treatment could keep a higher rate of commercially acceptable fruit, effectively prevent weight loss from longans, and retard the developments of aril breakdown and fruit disease in longan fruit. It could be concluded that 0.8 mM ATP treatment for 20 min could greatly delay longan fruit senescence, maintain higher fruit quality, and exhibit better storage behavior which might suggest a promising method for keeping quality and extending the shelf life of harvested “Fuyan” longan fruit.

A Review of Destructive and Non-destructive Methods for Determining Avocado Fruit Maturity

Abstract: Optimum harvest maturity is one of the important factors determining the quality of avocado fruit. Currently, avocado harvest maturity is mostly determined using markers or indices such as mesocarp oil, dry matter, or moisture content, all quantified destructively using representative samples of a batch in a consignment. Although useful, destructive techniques are time-consuming and results reflect properties of specific produce evaluated. High variation in maturity stages affect postharvest quality and the rate of ripening within a consignment, causing logistical difficulties. Emerging analytical techniques have particular advantages in non-destructive detection of food quality and safety. In this paper, destructive and non-destructive analytical methods and instruments for determining maturity parameters of avocado fruit are discussed. This review also looks at the trends in applying emerging optical and imaging techniques to the analysis of avocado fruit maturity and quality, in particular, visible to near infrared spectroscopy, ultrasonic system, ultrasound imaging, hyperspectral imaging, magnetic resonance imaging, and fluorescence imaging. On the basis of the observed trends, the technical challenges and future prospects for commercial application of these non-destructive techniques for maturity determination of individual avocado fruit are presented.

Method Development to Increase Protein Enrichment During Dry Fractionation of Starch-Rich Legumes

Abstract: A facile method was developed to establish milling settings that optimally separate starch granules from protein bodies and cell wall fibres for starch-rich legumes. Optimal separation was obtained for pea, bean, lentil and chickpea when the particle size distribution curve of flour and isolated starch granules overlap maximally. This outcome was based on scanning electron microscopy, protein content of the fine fraction and particle size distribution curves. Milling settings differed between legumes due to variances in seed hardness and starch granule size. The protein content of the fine fraction was legume specific as well and could be explained by differences in particle density, seed hardness, starch granule size, fat content and flour dispersibility.

Development and Characterization of an Active Chitosan-Based Film Containing Quercetin

Abstract: This work aims at developing an active chitosan film through the incorporation of quercetin and the evaluation of physical and functional properties of the films made thereof. The addition of quercetin showed to influence films’ properties in terms of surface morphology, tensile strength, and opacity while elongation-at-break, thickness, water vapor, and oxygen permeability were not significantly affected with incorporation of quercetin. The color parameters of chitosan films were affected by quercetin incorporation with a decrease of the values of L* and a*. The film exhibited a high free-radical scavenging activity, showing antioxidant activity. The film-forming solutions of chitosan with or without quercetin showed antibacterial activity against four Gram-negative and three Gram-positive bacteria. These results showed that quercetin incorporation in chitosan-based films has potential to be used as a solution for active food packaging.

Application of Electronic Nose with Multivariate Analysis and Sensor Selection for Botanical Origin Identification and Quality Determination of Honey

Abstract: Characterization of the botanical origin and quality of honeys is of great importance and interest in agriculture. In this study, an electronic nose (e-nose) was applied for identifying the botanical origin of honey as well as determining their main quality components such as glucose, fructose, hydroxymethylfurfural (HMF), amylase activity (AA), and acidity. Principal component analysis (PCA) and discriminant factor analysis (DFA) were employed to generate scatter plots of honey samples from 14 botanical origins. Origin discrimination models with 100 % overall accuracy were established by least squares support vector machines (LS-SVM). LS-SVM outperformed the linear regression method of partial least squares regression (PLSR) for quality prediction, showing that the non-linear correlations between e-nose responses were important for the analysis of honey. Moreover, three sensor selection algorithms, namely, uninformation variable elimination (UVE), successive projections algorithm (SPA), and competitive adaptive reweighted sampling (CARS) were applied for the first time to analyze e-nose fingerprints of honey. After the calculation of the above three algorithms and the comparison of their results, from a total of 18 sensors, the important ones were selected for glucose (three), fructose (five), HMF (three), AA (five), and acidity (four) prediction, respectively. The results of sensor selection show the advantages of reducing redundancy of e-nose data, optimizing the sensor array of an e-nose, and improving the performance of models in terms of robustness. The overall results show that the laborious, time-consuming, and destructive analytical methods like high-performance liquid chromatography (HPLC), acid-base titration, and spectrophotometry could be replaced by e-nose to provide a rapid and non-invasive determination of the botanical origin and quality of honey.

Postharvest Handling and Storage of Fresh Cassava Root and Products: a Review

Abstract: The increase in global demand for healthy food products and initiatives to ensure food security in developing countries has focused on the cultivation of drought-resistant and biofortified cassava varieties. Cassava is a staple root crop grown in subtropical and tropical climates. Cassava flour is gluten free, which can be used as composite flour in essential foods such as bread. Thus, the role of postharvest handling of freshly harvested cassava root is essential, owing to the rapid physiological deterioration of the root soon after harvest. This situation confers a limited shelf life and, thus, creates poor utilization of the cassava root. However, processing cassava root into other food forms such as fufu, garri, starch and high-quality flour enhances stability and long-term storage. This article critically reviewed the postharvest handling, processing and storage of fresh cassava root. Highlighting on the role of storage and minimal processing on sustainable cassava production, various spoilage mechanisms of cassava root were identified. In developing countries, cassava root is a valuable food and energy source, and understanding the role of optimum postharvest handling, processing and storage techniques would alleviate some concerns of food insecurity.

Application of Wavelet Analysis to Spectral Data for Categorization of Lamb Muscles

Abstract: Application of wavelet analysis to near-infrared (NIR) hyperspectral imaging data was exploited for categorization of lamb muscles in this study. A variety of common wavelet transforms was investigated to identify the best wavelet features for categorization of lamb muscles. The fifth-order Daubechies wavelet (“db5”) was found to be the best wavelet function for decomposition of lamb spectral signal. Features of wavelet coefficients extracted from db5 wavelet at the fifth decomposition level were then used as the inputs of least-squares support vector machine (LS-SVM) for developing classification models. Principal component analysis (PCA) was used for dimensionality reduction. Classification performance of LS-SVM classifiers in tandem with wavelet transform and PCA was compared with the LS-SVM models based on original, first derivative, second derivative, smoothing, standard normal variate (SNV), and multiplicative scatter correction (MSC) spectral data; then, the overall correct classification performance for the training and test sets using combination with wavelet approximation and detail coefficients in fifth decomposition scale and PCA was 100 and 96.15 %, respectively. In addition, the developed classification models were successfully applied to the hyperspectral images for obtaining classification maps and the kappa coefficient of 0.83 was obtained for the visual classification. The results revealed that the application of wavelet analysis has a great potential for categorization of lamb muscles in tandem with multivariate analysis and image processing.

Microencapsulation of Extra Virgin Olive Oil by Spray Drying: Effect of Wall Materials Composition, Process Conditions, and Emulsification Method

Abstract: The objective of the study was to investigate the microencapsulation of extra virgin olive oil by spray drying to increase its stability and application area. The effects of homogenization rate, pump rate, i.e., flow rate of feeding emulsion and wall materials composition on physical and chemical properties of microencapsulated extra virgin olive oil powder (MEVOP) were evaluated. Maltodextrin (MD) and whey protein isolate (WPI) were used as wall materials and microencapsulation was carried out in a laboratory type spray dryer. The MD:WPI ratio as mixture variable and pump and homogenization rates as process variables were arranged through D-optimal combined design. The optimum wall materials composition and microencapsulation process conditions were determined as follows: 92 % (db) MD, 7 % (db) WPI, and 1 % (db) Tween 20 as wall materials composition and 17,500 rpm and 22 % homogenization and pump rates, respectively. The results showed that the wall materials composition was the most effective independent variables on physical properties in terms of moisture content, water activity, bulk and particle properties of powder as well as microencapsulation efficiency and oxidation stability of MEVOP during converting liquid extra virgin olive oil to powder form. The effects of emulsification methods in terms of rotor-stator and ultrasonic homogenization on physical and chemical properties of MEVOP were also comparatively investigated in this study. The MEVOP produced by ultrasonic homogenization had smaller particle size and lower microencapsulation efficiency than that of rotor-stator homogenization method. But microcapsules obtained by ultrasonic homogenization had better oxidative stability.

Properties of Dietary Fibers from Agroindustrial Coproducts as Source for Fiber-Enriched Foods

Abstract: The importance of food fibers has led to the development of a large and potential market for fiber-enriched foods, and nowadays, there is an ongoing interest to find new sources of dietary fiber (DF), such as agroindustrial coproducts which have traditionally been undervalued. The aim of the article was to evaluate the suitability of five sources of DF to develop fiber-enriched foods. Proximate analysis and physicochemical, technological, and physiological properties (including cholesterol absorption capacity) of these DF sources were determined and compared. Not only proximate composition but also physicochemical and techno-functional properties of DF samples depend on the composition of the raw material (pomegranate, citrus, tiger nuts…), the industrial source, and the coproducts processing into DF extracts. Total dietary fiber content and the ratio insoluble/soluble dietary fiber determine the values obtained for these properties. However, cholesterol adsorption capacity seems to be influenced for other components linked to dietary fiber. Extracts rich in DF obtained from agroindustrial coproducts can be used as functional ingredients. The characterization of these extracts is very important to decide in which type of foods these fibers could be added without causing adverse changes in the food matrix. Pomegranate dietary fiber shows promising results principally about their cholesterol adsorption capacity which must be investigated in in vitro digestion process.

Ultrasound-Assisted Air-Drying of Apple (Malus domestica L.) and Its Effects on the Vitamin of the Dried Product

Abstract: This work has examined the influence of ultrasonic-assisted air-drying on the dehydration of apple (Malus domestica L. var Royal Gala) and its influence in the availability of vitamins A, B1, B2, B3, B5, B6, and E of the dried product. This study also has estimated the effective water diffusivity in air-drying process subjected to ultrasonic waves. The water effective diffusivity increased by up to 79 % by ultrasound application, which caused a reduction of about 35 % in the total drying time compared to the air-drying without sonication. The application of ultrasound increased the availability of vitamins B1, B2, B3, and B6 in the dried product. A loss of vitamins B5 and E were observed for all studied drying conditions.

Reversible Covalent Immobilization of Cinnamaldehyde on Chitosan Films via Schiff Base Formation and Their Application in Active Food Packaging

Abstract: In this work, cinnamaldehyde was reversibly anchored to chitosan films via imino-covalent bonding The Schiff base was synthesized in solid phase employing neutralized chitosan films immersed in acidified 95 % (v/v) ethanolic solution in which the aldehyde was dissolved The substitution degree (%) of cinnamaldehyde to the amine group was close to 70 % Attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) analysis revealed the formation of the chitosan-cinnamaldehyde Schiff base The hydrolysis of the imino bond and subsequent release of cinnamaldehyde were studied after the films had been subjected to different combinations of temperature/time treatments simulating food preservation methods The amount of aldehyde that remained covalently attached to the films was monitored by ATR-FTIR, and the substitution degree was determined by elemental analysis Surface contact angle and colour parameters of cinnamaldehyde-imine-chitosan films and these films subjected to different treatments were also evaluated The antimicrobial properties of chitosan-Schiff base films were tested in vitro against Staphylococcus aureus and Escherichia coli and in milk inoculated with Listeria monocytogenes The antimicrobial activity varied depending on the treatment applied and consequently the degree of imino bond hydrolysis achieved and cinnamaldehyde released Films of Schiff base-chitosan derivative subjected to different time/temperature treatments inhibited the growth of L monocytogenes for 12 days under refrigeration conditions, which may extend the microbiological shelf life of such products Sensory analysis of milk in contact with the films showed that a cinnamon smell does not cause any rejection among potential consumers These novel films could be used in the design of antimicrobial food packaging and in various other technological areas where sustained-release systems are required

Effect of an Edible Nanomultilayer Coating by Electrostatic Self-Assembly on the Shelf Life of Fresh-Cut Mangoes

Abstract: This work aims at evaluating the effect of an alginate-chitosan nanomultilayer coating, obtained by electrostatic layer-by-layer self-assembling, in the quality and shelf life of fresh-cut mangoes. Coated and uncoated fresh-cut mangoes were stored under refrigeration (8 °C) for 14 days. The changes in mass loss, titratable acidity, pH, ascorbic acid content, total soluble solids, malondialdehyde content, browning rate, and microbial count were evaluated during storage. At the end of the storage period, lower values of mass loss, pH, malondialdehyde content, browning rate, soluble solids, microorganisms’ proliferation, and higher titratable acidity were observed in the coated mangoes. The nanomultilayer coating did not improve the retention of vitamin C during storage of fresh-cut mangoes. Results suggest that chitosan-alginate nanomultilayer edible coating extends the shelf life of fresh-cut mangoes up to 8 days.

Grape Processing by High Hydrostatic Pressure: Effect on Microbial Populations, Phenol Extraction and Wine Quality

Abstract: Vitis vinifera (variety Tempranillo) grapes were subjected to high hydrostatic pressure (HHP) treatments of 200, 400 and 550 MPa for 10 min, and its effect on microbial populations, phenol extraction and wine quality was examined. At ≥400 MPa, the wild yeast population was strongly reduced from 104 to <10 cfu/ml. Bacteria showed greater resistance, and a residual load remained even after the treatment at 550 MPa. The extraction of phenolic compounds from the HHP-treated grapes was improved, with higher concentrations of total phenols obtained compared to crushing alone. Anthocyanin extraction was also increased, producing wines with better colour intensity. These wines also had higher methanol and ethanol contents and returned higher aromatic quality and colour scores. The HHP treatment of grapes may assist in the use of yeast starters, increase phenol extraction from grape skins and improve wine quality.

Potential of Electrolyzed Water as an Alternative Disinfectant Agent in the Fresh-Cut Industry

Abstract: Water disinfection is one of the most critical processing steps in fresh-cut vegetable production. Technologies capable for the efficient disinfection of process water and recycled water would allow reducing wastewater and have less impact on the environment. Among the chemical disinfectants, hypochlorite solutions are still the most widely used. Electrochemical disinfection of the wash water has been demonstrated to be effective in eliminating a wide spectrum of pathogens in process water. Both hypochlorite solutions and electrochemically produced chlorine compounds, in particular hypochlorous acid, are effective disinfectants when adequate doses are used. A new electrochemical process using boron-doped diamond electrodes can generate additional reactive oxidant species than chlorine and further enhance the disinfecting capacity. However, there are pros and cons on the use of one or other disinfectant agents. In this review, the technological advantages and the limitations of electrolyzed water, particularly regarding the organic matter content, are discussed and compared to the use of hypochlorite.

Suitability of Using Monolayered and Multilayered Emulsions for Microencapsulation of ω-3 Fatty Acids by Spray Drying: Effect of Storage at Different Temperatures

Abstract: Microencapsulation of ω-3 fatty acids by spray drying was studied using both monolayered (lecithin) and multilayered (lecithin-chitosan) fish oil emulsions with maltodextrin as wall material. Stability of the multilayered emulsions was higher than the monolayered ones, and increased with the increase of the concentration of chitosan. No differences were detected in the moisture or MY of the microcapsules related to the different composition of the corresponding emulsions. On the contrary, MEE was significant higher in the case of the microcapsules produced with the multilayered emulsions with the highest concentration of chitosan (1 % w/w), being related with lower detection of TBARS at high storage temperatures. Overall, this study shows the suitability of microencapsulating ω-3 fatty acids by spray drying using both monolayered and multilayered fish oil emulsions with maltodextrin as wall material. Multilayered microcapsules prepared with lecithin-chitosan emulsions provide a great protective effect against lipid oxidation of fish oil during storage at moderate to high temperatures (30 °C and 60 °C). These multilayered microcapsules could be therefore successfully used as a fish oil protection approach for storage before its use as an ingredient in food products.

Effects of High Oxygen Packaging on Tenderness and Water Holding Capacity of Pork Through Protein Oxidation

Abstract: The objective of this study was to investigate the biochemical difference of pork under high oxygen modified atmosphere packaging and their contribution to meat tenderness and water holding capacity of pork during postmortem storage. Twelve longissimus dorsi muscles were randomly assigned to either high oxygen modified atmosphere packaging or vacuum packaging and stored for 1, 4, and 6 days at 4 °C. The carbonyl content, protein surface hydrophobicity, protein solubility, calpain activity, desmin degradation, tenderness, and water loss of pork were determined. Results showed that carbonyl content, protein surface hydrophobicity, and protein solubility were significantly affected (P 0.05). Samples from high oxygen modified atmosphere packaging at 1 day showed greater intensity of intact 80 KDa calpain and lower intensity of autolyzed 76 KDa calpain product compared to samples from vacuum packaging (P 0.05). Higher intensity of intact desmin was observed in samples from high oxygen modified atmosphere packaging than vacuum packaging samples from 1 day of postmortem storage. Both packaging method and storage time showed significant effects (P < 0.05) on tenderness and water loss of pork muscle during postmortem storage. Changes in protein oxidation, calpain activation, and protein proteolysis of postmortem pork under high oxygen modified atmosphere packaging could help to explain decreased meat tenderness and increased centrifuge loss of pork.